中国农村水利水电Issue(8)：60-65,6.DOI:10.12396/znsd.2501565
考虑表层土厚度影响的双层河床桥墩局部冲刷特征分析
Analysis of Local Scour Characteristics of Double-Layer Riverbed Piers Considering the Influence of Topsoil Thickness
摘要
Abstract
Local scour at bridge piers over multi-layered riverbeds evolves more complicatedly than over single-layer beds.The thickness of the surficial soil layer directly affects the maximum scour depth and final scour-hole morphology,yet traditional predictors often ignore the influence of surface soil thickness on pier foundation risks.To address this gap,we conducted clear-water flume experiments on single-layer and dual-layer beds(coarse upper layer over a fine lower layer).A total of 34 tests were conducted:nine on a single-layer uniform sand bed and the remainder on a double-layer uniform sand bed.The surface-layer thickness hb ranged from 6.07 to 11.50 cm,and the approach discharge ranged from Q=32.5 to 52.5 L/s.By systematically varying approach flow velocity and surficial-layer thickness,we documented the temporal evolution and equilibrium morphology of scour pits.The results indicate that,under double-layer bed conditions,a pronounced rate jump occurs as the scour front approaches the interlayer interface,leading to a stepped scour-pit morphology characterized by a gentle upper slope and a steep lower drop.Increasing surficial-layer thickness attenuates energy transmission to the interface and fosters a secondary armor layer at the pit bottom,markedly suppressing erosion of the underlying sediment.Based on these experiments,we introduce a surface-thickness correction coefficient Kw into the HEC-18(CSU)equation.The modified formulation exhibits significantly improved predictive accuracy over the original,providing a reliable tool for erosion-control design and risk assessment under complex geological conditions.关键词
桥墩/局部冲刷/分层河床/模型试验/冲刷深度预测Key words
bridge piers/local scouring/stratified riverbed/modeling experiments/scour depth prediction分类
建筑与水利引用本文复制引用
李佳韬,吴龙华,杨校礼,李喜元..考虑表层土厚度影响的双层河床桥墩局部冲刷特征分析[J].中国农村水利水电,2026,(8):60-65,6.基金项目
江苏省优秀青年基金项目(BK20230099). （BK20230099）
